Without further details, it's impossible to determine whether it's a movie or a book. If it's a movie, we might expect to see scenes that vividly portray the son's life events. If it's a book, we could anticipate a more descriptive and introspective account of his story, with the author having the space to explore the son's thoughts and feelings more deeply.
I'm not sure. It could be either. There are many works, both in film and literature, that are based on true stories.
There's not enough information to tell. It might be a movie, which could bring the true story of the son to life on the big screen with actors and visual effects. Or it could be a book, where the author would use words to tell the detailed and perhaps more in - depth story of the son's real - life experiences.